1. Field of the Invention
The present invention relates to apparatus for controlling tension on devices for feeding strands of wire-like material and particularly to an improved device for applying an adjustable friction force against a wire supply bobbin and for locking the device in position to maintain the desired tension.
2. Description of the Prior Art
Present wire feeding devices used in multi-filament wire braiding machines have complex mechanisms for adjusting the tension on wire fed from supply bobbins. These usually employ ratchet and spring mechanisms which are cumbersome, costly and difficult to adjust and maintain at a desired tension. Another device for adjusting tension and friction on a bobbin supplying textile thread material uses an adjustable collar on a shaft to control spring tension on a friction disc, such as shown in U.S. Pat. No. 1,364,259. This device requires excessive manipulation with two hands and is subject to loosening. A further device, such as shown in U.S. Pat. No. 2,232,966, utilizes a tubular member to retain a tensioning spring on a shaft with a threaded follower adjusting the force on a friction element engaging a film reel. The shaft rotates with the reel and a screw locks the follower on the shaft to maintain the desired tension and friction. This device likewise requires much manipulation and frequent tightening. Other devices are known utilizing hollow cylinders with an internal wedge for locking elements in a desired position on a shaft, but these could not be used for adjusting tension in a rotating mechanism.